It is advantageous to position the clamping collar relative to the article to be clamped so as to ensure that the clamping is performed in the desired region. When the clamping serves not only to fasten the article to be clamped to some other article, but also to make that fastening leaktight, the need to have correct positioning is particularly acute.
In addition, it is advantageous to position the collar relative to the article to be clamped before said article is connected to another article to which it is to be fastened.
That makes it possible to pre-position the clamping collar, and, in particular, to deliver the article to be clamped as pre-equipped with the clamping collar.